The present invention relates to a fixing and transport device for transporting substrates into and through a vacuum treatment system comprising several stations.
The substrate holders to be used are either plate-shaped with cut-outs that accommodate the substrates, or frames with braces to which the workpieces or substrates to be processed are fixed.
A known device, for example, is described in the European patent application EP 0 544 995. A solid bottom part with two sets of wheels that correlate with one rail and one support bearing, holds a top part that is designed as a substrate holder. The bottom part serves as the base for the top part which has no other support and which is part of the transport system that transports the substrates through the vacuum treatment system. The substrate holder is only supported by this bottom part and is to be moved together with its upper part across walls and built-in parts such as laterally arranged coating sources at a constant distance.
The disadvantage of this arrangement is that the bottom part must be a very heavy construction, that it takes up much space and thereby greatly increases the height of the overall system.
Another disadvantage is that for vertical stabilization of the substrate holder the supporting component of the transport system requires a certain minimum distance to the overturning point of the substrate holder. This greatly enlarges also the vacuum chamber. In addition, such unilaterally supported transport systems have very narrow tolerances with respect to the perpendicularity of the substrate holder in relation to the process components.
The utilization of two rollers for driving and mechanical guidance of the supporting element for the substrate holder according to EP 0 544 995 has the additional disadvantage that abrasion particles are generated. Although the place where they are generated is located below the substrates, they can nevertheless penetrate into the coating zone.